Method and system for obtaining deformation stress increment of extremely thin layered soft surrounding rock

Abstract

The application discloses a kind of deformation stress increment acquisition method and system of extremely thin layered soft surrounding rock;It is related to the technical field of tunnel engineering;The strain increment matrix of extremely thin layered soft surrounding rock under overall coordinate system is obtained, and under the elastic assumption theory, the stress tensor matrix of extremely thin layered soft surrounding rock under overall coordinate system is calculated by combining rotation matrix and element stiffness matrix, and the deformation stress increment is calculated according to the stress tensor matrix after characteristic correction;The method is improved on the basis of traditional extremely thin layered surrounding rock mechanics characteristic simulation technology, and under the elastic assumption theory, the stress increment matrix of extremely thin layered soft surrounding rock under overall coordinate system is calculated based on strain increment matrix, rotation matrix and element stiffness matrix;The deformation stress increment is calculated after the characteristic correction of stress increment matrix, and the stress deformation characteristics of extremely thin layered soft surrounding rock are accurately and reasonably described, and the efficiency of extremely thin layered soft surrounding rock engineering analysis is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel engineering, and particularly relates to a deformation stress increment acquisition method and system for extremely thin layered soft surrounding rock. BACKGROUND

[0002] In tunnel engineering and underground cavern construction, accurate mechanical description of extremely thin layered surrounding rock is a prerequisite for implementing scientific support design. Such rock mass has significant heterogeneity and anisotropy characteristics, and its mechanical behavior is controlled by multiple coupling factors such as geometric distribution of interlayer structure surface, mechanical properties of rock mass base material and structure surface spacing. The current numerical simulation methods generally used at home and abroad mainly include the following four types:

[0003] The discrete element model (DEM) simulates the layered structure through the particle element discretization method, which can represent the broken characteristics of the rock mass, but has the problems of low calculation efficiency and high complexity of contact determination algorithm, especially in the case of large deformation of soft surrounding rock, numerical convergence difficulty easily occurs;

[0004] The contact surface model uses explicit interface elements to describe interlayer sliding, but has the defect of insufficient sensitivity to structure surface spacing parameters, and cannot accurately reflect the progressive failure process of thin layered rock mass (layer thickness <10 cm);

[0005] The pervasive joint model can consider the influence of multiple structure surfaces, but the constitutive relationship does not reasonably introduce the yield criterion of rock mass base material, resulting in the over-simplification of rock mass failure mechanism under high stress state;

[0006] The transversely isotropic pervasive joint model partially solves the problem of material anisotropy, but still has the following technical bottlenecks: the stiffness matrix does not establish the normal / tangential stiffness anisotropic mechanical mechanism; the equivalent continuous medium transformation criterion considering the structure surface spacing and layer thickness is not constructed; the multiscale coupling of rock mass base material elastic-plastic constitutive and structure surface plastic evolution cannot be realized.

[0007] The above methods have significant limitations in the application of extremely thin layered soft surrounding rock: first, the existing models generally use the assumption of stiffness isotropy, which is in conflict with the actual normal stiffness-tangential stiffness differentiation characteristics of thin layered rock mass; second, the structure surface spacing parameter is treated by averaging, ignoring the spacing gradient distribution law unique to thin layered structure; third, the existing algorithms do not establish the cooperative evolution equation of rock mass base material and structure surface plastic yield, resulting in distortion of the numerical reproduction of the progressive failure process of surrounding rock. These problems directly lead to conservative or insufficient support parameter design, and have caused many engineering accidents such as initial support intrusion and instability of the working face in deep buried soft surrounding rock tunnel engineering. SUMMARY

[0008] The technical problem to be solved by the present application is that the traditional simulation method of the mechanical properties of extremely thin layered surrounding rock has exposed significant limitations in the application of extremely thin layered soft surrounding rock, such as ignoring the spacing gradient distribution law of thin layered structure, low calculation efficiency, and high difficulty; the present application aims to provide a deformation stress increment acquisition method and system for extremely thin layered soft surrounding rock, which improves the method based on the traditional simulation technology of the mechanical properties of extremely thin layered surrounding rock, calculates the stress tensor matrix of the deformation of extremely thin layered soft surrounding rock in the global coordinate system based on the strain increment matrix of extremely thin layered soft surrounding rock, the rotation matrix and the element stiffness matrix under the elastic assumption theory, calculates the deformation stress increment after correcting the stress tensor matrix characteristics, accurately and reasonably describes the stress deformation characteristics of extremely thin layered soft surrounding rock, and improves the engineering analysis efficiency of extremely thin layered soft surrounding rock.

[0009] The present application is realized by the following technical solutions:

[0010] The present application provides a deformation stress increment acquisition method for extremely thin layered soft surrounding rock, the extremely thin layered soft surrounding rock is soft surrounding rock containing a group of extremely thin layered structural planes and satisfying the Mohr-Coulomb strength criterion, and the method comprises the following steps:

[0011] An overall coordinate system is constructed, and the structural plane information of the extremely thin layered soft surrounding rock is collected in the overall coordinate system;

[0012] A local coordinate system is constructed according to the structural plane information, and a rotation matrix from the overall coordinate system to the local coordinate system is constructed;

[0013] The stiffness parameters of the extremely thin layered soft surrounding rock are described in the local coordinate system, and an element stiffness matrix is constructed based on the stiffness parameters;

[0014] The strain increment matrix of the extremely thin layered soft surrounding rock in the overall coordinate system is acquired, and the stress tensor matrix under the elastic assumption of the deformation of the extremely thin layered soft surrounding rock in the overall coordinate system is calculated under the elastic assumption theory in combination with the rotation matrix and the element stiffness matrix;

[0015] The stress tensor matrix is corrected for plastic characteristics to calculate the actual deformation stress increment matrix.

[0016] Further optimization scheme is that the structural plane information comprises:

[0017] The unit normal vector, normal spacing, normal stiffness and shear stiffness of the structural plane in the overall coordinate system l j k n ; k s ;

[0018] The cohesion of the structural plane c j ​Young's modulus of elasticity φ j and dilatancy angle Ψ j ;

[0019] Young's modulus of elasticity of the rock mass base material E so Poisson's ratio v cohesion c internal friction angle φ and dilatancy angle Ψ .

[0020] Further optimization scheme is that the local coordinate system is constructed according to the structural plane information and the rotation matrix of the overall coordinate system to the local coordinate system, and the method comprises the following steps:

[0021] A local coordinate system satisfying the right-hand screw rule is constructed by taking the normal direction of the structural plane as the z' axis of the local coordinate system and taking the strike of the structural plane as the y' axis of the local coordinate system; wherein the z' axis takes the direction A as the positive direction, and the direction A is a direction with an angle ≤ 90° between the z' axis and the z axis of the overall coordinate system; the x' axis of the local coordinate system takes the direction B as the positive direction, and the direction B is a direction with an angle ≥ 90° between the x' axis and the z axis of the overall coordinate system;

[0022] According to the unit normal vector of the structural plane in the overall coordinate system, the unit direction vector of the local coordinate system in the overall coordinate system is calculated;

[0023] According to the unit direction vector of the local coordinate system in the overall coordinate system, the rotation matrix of the overall coordinate system to the local coordinate system is constructed.

[0024] Further optimization scheme is that the stiffness parameters of the extremely thin layered soft surrounding rock in the local coordinate system are described, and the method comprises the following steps:

[0025] The stiffness parameters of the extremely thin layered soft surrounding rock are described by using the transversely isotropic material method, and the stiffness parameters comprise: Young's modulus of elasticity perpendicular to the direction of the structural plane Young's modulus of elasticity parallel to the direction of the structural plane E' = E so Poisson's ratio of the x' axis direction and the y' axis direction in the structural plane Poisson's ratio of the x' axis direction, the y' axis direction and the z' axis direction in the structural plane v'=v , and shear modulus parallel to the layer ; .

[0026] Further optimization scheme is that the unit stiffness matrix is constructed based on the stiffness parameters, and the method comprises the following steps:

[0027] The first coefficient is calculated according to the following formulaM and the second coefficient n

[0028]

[0029]

[0030] based on the first coefficient M and the second coefficient n to construct an element stiffness matrix K:

[0031]

[0032] Further optimization scheme is that the strain increment matrix of the extremely thin layered soft surrounding rock under the overall coordinate system is obtained, and the stress tensor matrix under the elastic assumption when the extremely thin layered soft surrounding rock deforms under the overall coordinate system is calculated in combination with the rotation matrix and the element stiffness matrix under the elastic assumption theory; including method:

[0033] The strain increment matrix under the overall coordinate system is expressed in the form of a column vector, and the stress increment matrix under the elastic assumption and the local coordinate system is obtained according to the elastic assumption theory and the element stiffness matrix;

[0034] The stress increment matrix under the elastic assumption and the local coordinate system is converted into the stress increment matrix under the elastic assumption and the overall coordinate system based on the rotation matrix;

[0035] The existing stress tensor matrix under the overall coordinate system is preset, and the stress tensor matrix under the elastic assumption when the extremely thin layered soft surrounding rock deforms under the overall coordinate system is obtained in combination with the existing stress tensor matrix and the stress increment matrix under the elastic assumption and the overall coordinate system.

[0036] Further optimization scheme is that the method for correcting the plastic properties of the stress tensor matrix includes:

[0037] The stress tensor matrix is converted into the expression form of the principal stress space to calculate the substrate yield function value f s When the substrate yield function value f s ≤0, the stress tensor matrix is not subjected to substrate plastic correction; when the substrate yield function value f s >0, the stress tensor matrix is subjected to substrate plastic correction;

[0038] The stress tensor matrix under the local coordinate system after the substrate plastic property correction is used to calculate the structure surface yield function value f sj When the structure surface yield function value f sj ​​​​When the stress tensor matrix is ​​≤0, no structural surface plastic correction is applied; when the structural surface yield function value is ≤0, no structural surface plastic correction is applied. f sj When the value is greater than 0, the stress tensor matrix is ​​subjected to structural surface plastic correction.

[0039] A further optimized scheme includes the following method for correcting the plastic properties of the stress tensor matrix:

[0040] A substrate strain-assisted correction matrix is ​​constructed in principal stress space. This matrix is ​​then transformed into a local coordinate system expression and further converted into a column vector form. The substrate stress-assisted correction matrix in the local coordinate system is calculated based on the element stiffness matrix. This local coordinate system stress-assisted correction matrix is ​​then transformed into a substrate stress-assisted correction matrix S in principal stress space. The stress tensor matrix under the elastic assumption is transformed into a principal stress space expression. The substrate yield function value is calculated based on the stress tensor matrix in the principal stress space under the elastic assumption. The substrate yield plasticity multiplier is calculated based on the substrate yield function value under the Mohr-Coulomb strength criterion and the substrate stress-assisted correction matrix S in principal stress space. According to the yield plastic multiplier of the substrate The correction amount is obtained as Where D represents the rotation matrix from the global coordinate system to the principal stress space;

[0041] Construct the auxiliary correction matrix for structural surface strain, convert the auxiliary correction matrix for structural surface strain into column vector form, and calculate the auxiliary correction matrix for structural surface stress S in the local coordinate system based on the element stiffness matrix. j Based on the stress tensor matrix in the local coordinate system after correction for the plasticity properties of the substrate, the yield function value of the structural surface is calculated. The yield plasticity multiplier of the structural surface is then calculated based on the yield function of the structural surface under the Mohr-Coulomb strength criterion and the auxiliary correction matrix of the structural surface stress in the local coordinate system. According to the yield plastic multiplier of the structural surface The correction amount is: Where C represents the rotation matrix from the global coordinate system to the local coordinate system.

[0042] A further optimization scheme is that the calculation method for the actual deformation stress increment matrix includes:

[0043]

[0044] in, This represents the actual stress increment matrix; This represents the stress tensor matrix under the elasticity assumption.

[0045] The scheme also provides a deformation stress increment acquisition system of an extremely thin layered soft surrounding rock, which is used for realizing the deformation stress increment acquisition method of the extremely thin layered soft surrounding rock.

[0046] The acquisition module is configured to construct a global coordinate system and acquire structural plane information of the extremely thin layered soft surrounding rock under the global coordinate system.

[0047] The construction module is configured to construct a local coordinate system and a rotation matrix of the global coordinate system to the local coordinate system according to the structural plane information.

[0048] The description module is configured to describe a stiffness parameter of the extremely thin layered soft surrounding rock under the local coordinate system and construct an element stiffness matrix based on the stiffness parameter.

[0049] The calculation module is configured to acquire a strain increment matrix of the extremely thin layered soft surrounding rock under the global coordinate system, and calculate a stress tensor matrix of the extremely thin layered soft surrounding rock under the elastic assumption when the extremely thin layered soft surrounding rock deforms under the global coordinate system, in combination with the rotation matrix and the element stiffness matrix under the elastic assumption theory.

[0050] The correction calculation module is configured to correct the stress tensor matrix for plastic characteristics and calculate an actual deformation stress increment matrix.

[0051] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0052] 1. The deformation stress increment acquisition method and system of the extremely thin layered soft surrounding rock provided by the present application are improved in method based on the traditional extremely thin layered surrounding rock mechanical property simulation technology, the stress tensor matrix of the extremely thin layered soft surrounding rock deforming under the global coordinate system is calculated in combination with the rotation matrix and the element stiffness matrix under the elastic assumption theory based on the strain increment matrix of the extremely thin layered soft surrounding rock, the deformation stress increment is calculated after the stress increment matrix is corrected for plastic characteristics, the stress and deformation characteristics of the extremely thin layered soft surrounding rock are accurately and reasonably described, so as to be used for the extremely thin layered soft surrounding rock simulation in the continuous medium model such as the finite element model and the finite difference model, and the analysis efficiency of the extremely thin layered soft surrounding rock engineering is improved.

[0053] 2. The deformation stress increment acquisition method and system of the extremely thin layered soft surrounding rock provided by the present application considers the coupling of the substrate yield failure and the structural plane yield failure, the whole calculation process conforms to the mathematical principle of plastic mechanics, the calculation of the deformation stress increment at each step is more in line with the actual situation than the previous achievements, the plastic zone distribution of the surrounding rock, the deformation distribution of the surrounding rock, the stress and deformation of the supporting structure and other construction effects obtained by using the method are more accurate in the rock and soil engineering field such as the tunnel and the slope, and the guiding value for the engineering design and construction is higher. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings:

[0055] Figure 1 Flowchart of the method for obtaining the deformation stress increment of the extremely thin layered soft surrounding rock;

[0056] Figure 2 Structure diagram of the system for obtaining the deformation stress increment of the extremely thin layered soft surrounding rock;

[0057] Figure 3 Diagram for comparing the calculation results of the method and the traditional method. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solutions and advantages of the present application more clear and understandable, the following will further describe the present application in combination with the embodiments and drawings. The exemplary embodiments of the present application and the descriptions thereof are only used to explain the present application, and should not be considered as a limitation to the present application.

[0059] For the traditional simulation method of the mechanical properties of the extremely thin layered surrounding rock, the following significant limitations are exposed in the application of the extremely thin layered soft surrounding rock: the spacing gradient distribution law of the thin layered structure is ignored, the calculation efficiency is low, and the difficulty is high. In view of this, the present application provides the following embodiments to solve the above technical problems.

[0060] Embodiment 1

[0061] The present embodiment provides a method for obtaining the deformation stress increment of the extremely thin layered soft surrounding rock, as shown in Figure 1 The extremely thin layered soft surrounding rock is a soft surrounding rock containing a group of extremely thin layered structural planes and satisfying the Mohr-Coulomb strength criterion, and the method comprises the following steps:

[0062] Step 1: Construct the overall coordinate system and collect the structural plane information of the extremely thin layered soft surrounding rock under the overall coordinate system; construct the spatial rectangular coordinate system oxyz The overall coordinate system is generally with the gravity direction as the z-axis, the x-axis and the y-axis in the horizontal plane, and the angle between them is 90°, and the coordinate system oxyz satisfies the right-hand screw rule.

[0063] The structural plane information includes: the unit normal vector of the structural plane under the overall coordinate system n x , n y , n z) n z Normal distance l j Normal stiffness k n Shear stiffness k s Cohesion of structural plane c j Internal friction angle φ j Dilatancy angle Ψ j Young's modulus of rock matrix (without structural plane) E so Poisson's ratio v Cohesion c Internal friction angle φ Dilatancy angle Ψ .

[0064] Step two, constructing a local coordinate system and a rotation matrix of the overall coordinate system to the local coordinate system according to the structural plane information; the step specifically includes the following methods:

[0065] Taking the normal direction of the structural plane as the z' axis of the local coordinate system and taking the strike direction of the structural plane as the y' axis of the local coordinate system to construct a local coordinate system satisfying the right-hand screw rule; wherein the z' axis takes the direction A as the positive direction, and the direction A is a direction with an angle ≤90° between the z' axis and the z axis of the overall coordinate system; the x' axis of the local coordinate system takes the direction B as the positive direction, and the direction B is a direction with an angle ≥90° between the x' axis and the z axis of the overall coordinate system;

[0066] According to the unit normal vector of the structural plane under the overall coordinate system, the unit direction vector of the local coordinate system under the overall coordinate system is calculated; specifically, the unit normal vector of the structural plane under the overall coordinate system is taken as the z' axis of the local coordinate system, and the x' axis and the y' axis of the local coordinate system are calculated according to the following formula: n x , n y , n z The expression of the unit direction vector of the x' axis, the y' axis and the z' axis in the local coordinate system o'x'y'z' in the overall coordinate system is calculated; oxyz

[0067] When n x = n y =0, the unit direction vector of the x' axis in the local coordinate system o'x'y'z' is:

[0068] x' The unit direction vector of the y' axis in the local coordinate system o'x'y'z' is: ;

[0069] y' ​Unit directional vector of the axis ;

[0070] z' Unit directional vector of the axis ;

[0071] When n x ≠0 or n y ≠0:

[0072] z' Unit directional vector of the axis ;

[0073] y' Unit directional vector of the axis ;

[0074] x' Unit directional vector of the axis .

[0075] According to the unit directional vector of the local coordinate system under the overall coordinate system, a rotation matrix C of the overall coordinate system to the local coordinate system is constructed; ;

[0076] Step three, describe the stiffness parameters of the extremely thin layered soft surrounding rock in the local coordinate system, and construct an element stiffness matrix based on the stiffness parameters; in this step, the stiffness parameters of the extremely thin layered soft surrounding rock in the local coordinate system; the method comprises:

[0077] The stiffness parameters of the extremely thin layered soft surrounding rock are described by using the transversely isotropic material method, it is assumed that the structural plane only affects the Young's modulus perpendicular to the structural plane direction and the shear modulus parallel to the structural plane direction, and the normal spacing of the structural plane is used l j , the shear stiffness of the structural plane k s , the normal stiffness of the structural plane k n , the Young's modulus of the rock mass base material (without structural plane) E so , Poisson's ratio v to calculate the stiffness parameters: the Young's modulus perpendicular to the structural plane direction , the Young's modulus parallel to the structural plane direction E' = E so , the Poisson's ratio of the x' axis direction and the y' axis direction in the structural plane , the Poisson's ratio of the x' axis direction, the y' axis direction and the z' axis direction in the structural plane v'=v , and the shear modulus parallel to the layer ; ; Gso This represents the shear modulus of elasticity of rock.

[0078] The method for constructing the element stiffness matrix based on stiffness parameters includes:

[0079] The first coefficient is calculated according to the following formula. M Second coefficient n :

[0080] ;

[0081] ;

[0082] Based on the first coefficient M Second coefficient n Construct the element stiffness matrix K:

[0083] .

[0084] Step four involves obtaining the strain increment matrix of the extremely thin layered weak surrounding rock in the global coordinate system, and then, combining the rotation matrix and element stiffness matrix under the elastic assumption, calculating the stress tensor matrix under the elastic assumption when the extremely thin layered weak surrounding rock undergoes deformation in the global coordinate system. This step specifically includes the following methods:

[0085] The strain increment matrix in the global coordinate system Represented as a column vector Based on the elasticity assumption theory and the element stiffness matrix, the stress increment matrix under the elasticity assumption and the local coordinate system is obtained; the column vector form of the obtained stress increment matrix under the elasticity assumption and the local coordinate system is then determined. The stress increment matrix under the elastic assumption and local coordinate system is obtained. .

[0086] Specifically, let any symmetric matrix A 3×3 The operational rules for writing it as a column vector consisting of 6 components are as follows: In any rectangular coordinate system, x corresponds to 1, y corresponds to 2, and z corresponds to 3.

[0087] Based on the rotation matrix C, the stress increment matrix under the elastic assumption and local coordinate system will be... This is transformed into a stress increment matrix under the elastic assumption and global coordinate system. : ;

[0088] Preset global coordinate system existing stress tensor matrix By combining the existing stress tensor matrix and the stress increment matrix under the elastic assumption and the global coordinate system, the stress tensor matrix of the extremely thin layered weak surrounding rock undergoing deformation in the global coordinate system is obtained. : .

[0089] Step 5: Correct the stress tensor matrix for plasticity characteristics and calculate the actual deformation stress increment matrix.

[0090] In this step, the characteristic correction of the stress tensor matrix includes the following methods:

[0091] Let the first principal stress, the second principal stress, and the third principal stress be respectively , , The rock substrate satisfies the Mohr-Coulomb strength criterion, and the stress tensor matrix is... Transformed into a principal stress space representation ,according to and formula Calculate the yield function value of the substrate f s ; Substrate plastic potential function ,in, , ;in, , These represent intermediate parameters related to the internal friction angle and the shear dilatation angle, respectively. Indicates the internal friction angle of the rock; Represents the shear dilatation angle of the rock; when the base material yield function value f s When the stress tensor value is ≤0, no substrate plasticity correction is applied to the stress tensor matrix; when the substrate yield function value is ≤0, no substrate plasticity correction is applied. f s When the stress tensor matrix is ​​greater than 0, the substrate plasticity is corrected.

[0092] To perform substrate yield correction on the stress increment matrix, the correction amount can be obtained using the following methods:

[0093] Constructing the auxiliary matrix for plastic strain of the substrate: Convert P to its local coordinate system representation. ,Will Convert to column vector form ,according to column vector form Then, the substrate stress-assisted correction matrix S1 is obtained, and the stress-assisted correction matrix S1 is transformed into the principal stress space expression form. According to the formula and substrate yield function value f s Calculate the yield plasticity multiplier of the substrate According to the yield plastic multiplier of the substrate The correction amount is obtained as ; wherein S represents the principal stress space expression form of the substrate stress auxiliary correction matrix; D represents the rotation matrix of the global coordinate system to the principal stress space, which is derived from the stress tensor matrix C represents the rotation matrix of the global coordinate system to the local coordinate system, which can be uniquely determined;

[0094] The structure surface yield function under the Mohr-Coulomb strength criterion is: The structure surface plastic potential function is: First, determine whether to perform substrate plasticity correction, and calculate the stress tensor matrix in the global coordinate system after the substrate plasticity correction The calculation method is:

[0095]

[0096] Convert to the stress increment matrix in the local coordinate system after the substrate plasticity correction , and calculate the structure surface yield function value f sj ; when the structure surface yield function value f sj ≤0, no structure surface plasticity correction is performed on the stress tensor matrix; when the structure surface yield function value f sj >0, the structure surface plasticity correction is performed on the stress tensor matrix.

[0097] If the structure surface plasticity correction is performed on the stress increment matrix, the correction amount acquisition method includes:

[0098] Construct a structure surface strain auxiliary correction matrix :

[0099] ,

[0100] Convert the structure surface strain auxiliary correction matrix to a column vector form , calculate and convert to S j , and the yield function is: , combined with the structure surface stress auxiliary correction matrix and the structure surface yield function value f sj Calculate the structure surface yield plastic multiplier , according to the structure surface yield plastic multiplier , the correction amount is: ; wherein S j represents the structure surface stress auxiliary correction matrix; C represents the rotation matrix of the global coordinate system to the local coordinate system.

[0101] The stress tensor matrix based on the characteristics is corrected to calculate an actual stress increment; the method comprises:

[0102]

[0103] Wherein, The actual stress increment matrix is represented by The stress increment matrix under the elastic assumption is represented by

[0104] Embodiment 2

[0105] The embodiment provides a deformation stress increment acquisition system for extremely thin layered soft surrounding rock, which is used to realize the deformation stress increment acquisition method for extremely thin layered soft surrounding rock in embodiment 1; as shown in the figure, Figure 2 The system comprises:

[0106] The acquisition module is used to construct a global coordinate system and acquire the structural plane information of the extremely thin layered soft surrounding rock under the global coordinate system;

[0107] The construction module is used to construct a local coordinate system and a rotation matrix from the global coordinate system to the local coordinate system according to the structural plane information;

[0108] The description module is used to describe the stiffness parameters of the extremely thin layered soft surrounding rock under the local coordinate system and construct an element stiffness matrix based on the stiffness parameters;

[0109] The calculation module is used to acquire the strain increment matrix of the extremely thin layered soft surrounding rock under the global coordinate system, and calculate the stress tensor matrix under the elastic assumption when the extremely thin layered soft surrounding rock deforms under the global coordinate system in combination with the rotation matrix and the element stiffness matrix under the elastic assumption theory;

[0110] The correction calculation module is used to correct the stress tensor matrix according to the plastic characteristics to calculate the actual deformation stress increment matrix.

[0111] Embodiment 3

[0112] The embodiment provides a computer readable medium, which stores a computer program, and the computer program is executed by a processor to realize the deformation stress increment acquisition method for extremely thin layered soft surrounding rock in embodiment 1, and the following steps are specifically executed:

[0113] Step one, constructing a global coordinate system and acquiring the structural plane information of the extremely thin layered soft surrounding rock under the global coordinate system;

[0114] Step two, constructing a local coordinate system and a rotation matrix from the global coordinate system to the local coordinate system according to the structural plane information;

[0115] Step three, describe the stiffness parameters of the extremely thin layered soft surrounding rock in the local coordinate system, and construct the unit stiffness matrix based on the stiffness parameters;

[0116] Step four, obtain the strain increment matrix of the extremely thin layered soft surrounding rock in the global coordinate system, and combine the rotation matrix and the unit stiffness matrix to calculate the stress tensor matrix of the extremely thin layered soft surrounding rock under the elastic assumption when deformation occurs in the global coordinate system under the elastic assumption theory;

[0117] Step five, correct the plastic properties of the stress tensor matrix to calculate the actual deformation stress increment matrix.

[0118] The known structural plane unit normal vector in the embodiment The normal spacing of the structural plane is 0.1 m, and the normal stiffness is k n = 1.5×10 11 Pa / m, the tangential stiffness is k s = 5×10 8 Pa / m. The structural plane cohesion is c j =5×10 4 Pa, the internal friction angle is φ j =18°, and the dilatancy angle is Ψ j =0°; the Young's modulus of the rock mass base material is E so =1×10 9 Pa, the Poisson's ratio is v =0.3, the cohesion is c =1×10 5 Pa, the internal friction angle is φ =24°, and the dilatancy angle is Ψ =0°.

[0119] The stress increment in the global coordinate system is , the current stress state is , the deformation stress increment matrix calculated according to the conventional transversely isotropic joint model (without considering the base material yield) is , the deformation stress increment matrix calculated according to the method (considering the base material yield) is , and the deformation stress increment results obtained according to the conventional method and the method of the application are shown in Figure 3 As can be seen from the figure, the stress increment calculation result of the method is more accurate than that of the conventional method, which further makes the distribution of the plastic zone of the surrounding rock, the deformation distribution of the surrounding rock, and the stress and deformation of the supporting structure in the construction effect more accurate.

[0120] The above detailed description of the specific embodiments of the present application has been given to understand the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for obtaining deformation stress increment of an extremely thin layered soft weak surrounding rock, characterized in that, The extremely thin layered soft surrounding rock is a soft surrounding rock containing a group of extremely thin layered structural planes and satisfying the Mohr-Coulomb strength criterion, and the method comprises the following steps: An overall coordinate system is constructed, and structural plane information of the extremely thin layered soft surrounding rock is collected under the overall coordinate system; A local coordinate system is constructed according to the structural plane information, and a rotation matrix of the overall coordinate system to the local coordinate system is constructed; Stiffness parameters of the extremely thin layered soft surrounding rock are described under the local coordinate system, and an element stiffness matrix is constructed based on the stiffness parameters; A strain increment matrix of the extremely thin layered soft surrounding rock under the overall coordinate system is obtained, and a stress tensor matrix under the elastic assumption of the extremely thin layered soft surrounding rock when deformation occurs is calculated under the elastic assumption theory, in combination with the rotation matrix and the element stiffness matrix; the method comprises the following steps: The strain increment matrix under the overall coordinate system is expressed in the form of a column vector, and a stress increment matrix under the elastic assumption and the local coordinate system is obtained according to the elastic assumption theory and the element stiffness matrix; The stress increment matrix under the elastic assumption and the local coordinate system is converted into a stress increment matrix under the elastic assumption and the overall coordinate system based on the rotation matrix; A preset existing stress tensor matrix under the overall coordinate system is obtained, and a stress tensor matrix under the elastic assumption of the extremely thin layered soft surrounding rock when deformation occurs is obtained in combination with the existing stress tensor matrix and the stress increment matrix under the elastic assumption and the overall coordinate system; The stress tensor matrix is corrected for plastic properties, and an actual deformation stress increment matrix is calculated; The method for correcting the stress tensor matrix for plastic properties comprises the following steps: The base material strain auxiliary correction matrix of the principal stress space is constructed, the base material strain auxiliary correction matrix is converted into an expression form of a local coordinate system and into a column vector form, the base material stress auxiliary correction matrix under the local coordinate system is calculated according to the unit stiffness matrix, the base material stress auxiliary correction matrix under the local coordinate system is converted into the base material stress auxiliary correction matrix S under the principal stress space, the stress tensor matrix under the elastic assumption is converted into an expression form of the principal stress space, the base material yield function value is calculated according to the stress tensor matrix under the principal stress space of the elastic assumption, and the base material yield plasticity multiplier is calculated based on the base material yield function value under the Mohr-Coulomb strength criterion and the base material stress auxiliary correction matrix S under the principal stress space , and the correction amount is obtained according to the base material yield plasticity multiplier ; wherein D represents a rotation matrix from the overall coordinate system to the principal stress space. The structural plane strain auxiliary correction matrix is constructed, the structural plane strain auxiliary correction matrix is converted into a column vector form, the structural plane stress auxiliary correction matrix S in a local coordinate system is calculated according to an element stiffness matrix j ; the stress tensor matrix in the local coordinate system after correction according to the plasticity characteristics of the base material is corrected, the structural plane yield function value is calculated, the structural plane yield plasticity multiplier is calculated based on the structural plane yield function under the Mohr-Coulomb strength criterion and the structural plane stress auxiliary correction matrix in the local coordinate system , and the correction amount is obtained according to the structural plane yield plasticity multiplier . ; wherein C represents a rotation matrix from the global coordinate system to the local coordinate system.

2. The method according to claim 1, wherein the method is characterized by, The structural plane information comprises the following steps: unit normal vector of the structural plane in the global coordinate system, normal distance l j , normal stiffness k n , and shear stiffness k s ; cohesion c of the structural plane j , internal friction angle φ j and dilatancy angle Ψ j ; Young's modulus of elasticity E of the rock mass substrate so , Poisson's ratio v, cohesion c, internal friction angle φ and dilatancy angle Ψ.

3. The method according to claim 2, wherein, The method for constructing the local coordinate system according to the structural plane information and the rotation matrix of the overall coordinate system to the local coordinate system comprises the following steps: A local coordinate system satisfying the right-hand screw rule is constructed by taking the normal direction of the structural plane as the z' axis of the local coordinate system and taking the strike of the structural plane as the y' axis of the local coordinate system; wherein the z' axis takes direction A as the positive direction, and the direction A is a direction with an angle ≤ 90° between the z' axis and the z axis of the overall coordinate system; the x' axis of the local coordinate system takes direction B as the positive direction, and the direction B is a direction with an angle ≥ 90° between the x' axis and the z axis of the overall coordinate system; A unit direction vector of the local coordinate system under the overall coordinate system is calculated according to a unit normal vector of the structural plane under the overall coordinate system; A rotation matrix of the overall coordinate system to the local coordinate system is constructed according to the unit direction vector of the local coordinate system under the overall coordinate system. The stiffness parameters of the extremely thin layered soft surrounding rock are described under the local coordinate system; 4. The method according to claim 3, wherein, The method comprises the following steps: The method for constructing the element stiffness matrix based on the stiffness parameters comprises the following steps: The stiffness parameters of the extremely thin layer soft surrounding rock are described by using a transversely isotropic material method, and the stiffness parameters include: Young's modulus E perpendicular to the direction of the structural plane , Young's modulus E' = E parallel to the direction of the structural plane so , Poisson's ratios in the x' axis direction and the y' axis direction in the structural plane , Poisson's ratios v' = v in the x' axis direction, the y' axis direction and the z' axis direction in the structural plane, and a shear modulus parallel to the layer . .

5. The method according to claim 4, wherein the method is characterized by, A first coefficient M and a second coefficient n are calculated according to the following formula: The element stiffness matrix K is constructed based on the first coefficient M and the second coefficient n: ； ； The method for correcting the stress tensor matrix for plastic properties comprises the following steps: 。 6. The method according to claim 1, wherein the method is characterized by, The method for calculating the actual deformation stress increment matrix comprises the following steps: The substrate yield function value f is calculated by converting the stress tensor matrix into the expression form of the principal stress space s ; when the substrate yield function value f s ≤ 0, no substrate plasticity correction is performed on the stress tensor matrix; when the substrate yield function value f s > 0, the substrate plasticity correction is performed on the stress tensor matrix; The yield function value f of the structural plane is calculated based on the stress tensor matrix in the local coordinate system after correction according to the plastic properties of the base material sj ; When the structural plane yield function value f sj ≤0, no plastic correction is made to the stress tensor matrix; when the structural plane yield function value f sj >0, plastic correction is made to the stress tensor matrix.

7. The method according to claim 1, wherein the method is characterized by, A system for implementing the deformation stress increment acquisition method of the extremely thin layered soft surrounding rock according to any one of claims 1-7; the system comprises: ； wherein, denotes the actual stress increment matrix; denotes the stress tensor matrix under the elastic assumption.

8. A system for obtaining deformation stress increment of an extremely thin layered soft weak surrounding rock, characterized in that, A collection module is configured to construct an overall coordinate system and collect structural plane information of the extremely thin layered soft surrounding rock under the overall coordinate system; ​ The construction module is configured to construct a local coordinate system and a rotation matrix of the global coordinate system to the local coordinate system according to the structural plane information; The description module is configured to describe the stiffness parameters of the extremely thin layered soft and weak surrounding rock in the local coordinate system, and construct an element stiffness matrix based on the stiffness parameters; The calculation module is configured to obtain a strain increment matrix of the extremely thin layered soft and weak surrounding rock in the global coordinate system, and calculate a stress tensor matrix of the extremely thin layered soft and weak surrounding rock under the elastic assumption when the deformation occurs in the global coordinate system, in combination with the rotation matrix and the element stiffness matrix under the elastic assumption theory; The correction calculation module is configured to correct the stress tensor matrix for plastic characteristics, and calculate an actual deformation stress increment matrix.

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